Telescopic jibs

ABSTRACT

This invention relates to a locking device for a telescopic jib constituted by at least three sections and by a motive member connected between the first and second sections, and comprising at least one bolt capable of integrating the second and third sections in their relative end positions, wherein this bolt is arranged on the rear end of the third section and may be selectively inserted into at least three catches, said catches being respectively unitary with the rear end of the second section, with an element unitary with the first section and with the front end of the second section, whilst the second catch is arranged near the front end of the first section.

United States Patent Cheze [451 June 20, 1972 TELESCOPIC JIBS 2,589,0803/1952 Heinish... ....52/1 18 I 2,173,095 9/1939 Byme ...52/1l5 [72]Invent 322: Chen 3,088,543 5/1963 Moller ..182/67 [73] Assignee: PotainPoclain Materiel, Saone-et-Loire, FOREIGN PATENTS OR APPLICATIONS France723,535 6/1942 Germany ..52 1 1 1 Filed: 2 l,430,l68 France ..52/l l8 [2l N 30 523 729,186 7/1932 France ..343/90] 1] App 0;:

7 Primary Examiner-Henry C. Sutherland Assistant Examiner-Leslie A.Braun Apphcam Att0rneyWard, McElhannon, Brooks & Fitzpatrick April 21,1969 France.....' ..6912472 [57] ABSTRACT i 52/115 248/354 Th1s1nvent1on relates to a locking devlcc for a telescopic 11b 58] Fieid 1i8 632 constituted by at least three sections and by a motive member343/883 /354 i 2 H 5 connected between the first and second sections,and comprising at least one bolt capable of integrating the second and 7third sections in their relative end positions, wherein this bolt [56]References cued is arranged on the rear end of the third section and maybe UNiTED STATES PATENTS selectively inserted into at least threecatches, said catches being respectively unitary with the rear end ofthe second sec- 3,398,645 7/1968 Nans el ..52/1 15 tioh with an elementunitary with the f t Section and with the 2,685,353 8/1954 Cask1e..248/354 P from end f the Second section, whilst the second catch is 1g ranged near the front end of the first section. enc am... 3,296,7571/1967 Goodman ..52/1 1 l 4 Claims, 3 Drawing Figures 7 5 1 6 8 a 2 I 7/I0 9 \l/ I 1 I 522% l t I 1 PKTENTEDJum 1972 SHEET 2 0F 2 TELESCOPICJIBS The present invention relates to telescopic jibs, with whichcertain cranes are provided, and more particularly to a locking devicefor a telescopic jib having at least three sections.

It is known to expand the different sections of jibs that have at leastthree sections.

As is known, a first ram is arranged between the first and secondsections and a second ram between the second and third sections. Thisarrangement, which requires the use of two rams, generally leads toheavy and cumbersome equipment.

In order to obviate these disadvantages, the applicants have conceived adevice for locking the different sections together, which, whenoperating in successive phases, enables the different sections of atelescopic jib comprising at least three sections to be extended out,with one ram connected between two of the sections.

The invention therefore has for its subject a locking device for atelescopic jib constituted by at least three sections and by a motivemember, preferably a ram, connected between the first and secondsections.

This device comprises at least one bolt arranged at the rear end of thethird section and capable of being selectively inserted into at leastthree catches. These catches are unitary, respectively, with the rearend of the second section, with an element unitary with the firstsection and with the front end of the second section, the second catchmoreover being arranged near the front end of the first section.

According to a preferred embodiment, the bolt is constituted by fingersmounted to slide in a slideway unitary with the third section, capableof being actuated by a ram.

Moreover, the catches are advantageously constituted by apertures madein the elements with which they are unitary.

Finally, the element with which the second catch is unitary may beconstituted by a rod fixed to the inner face of the bottom of the firstsection. 1

The invention will be described in greater detail with reference to theaccompanying drawings, in which:

FIG. 1 is a schematic section through a telescopic jib provided with thelocking device according to the invention;

FIG. 2 and 3 are partial views in section of a telescopic jib providedwith the device according to the invention.

Referring now to the drawings, FIG. 1 shows a telescopic jib comprisingthree sections. In the present case, section 1 constitutes the bottomsection articulated to the turret or the platform of a crane, section 2is an intermediate section and section 3 is usually designated as boomsection. The jib is in the non-telescoped out position, so that section3 is arranged inside section 2, which is itself arranged insidesection 1. A motive member, such as a hydraulic ram 4, is connectedbetween sections 1 and 2.

A device with bolt 5 is arranged at the end of the section 3 andcomprises at least one bolt such as fingers 6 or 7 mounted to pivot onthe element 3 in the schematic representation shown. Finger 6 maycooperate with catches 8 and 9 unitary with section 2 and respectivelyarranged at the level of the rear and front ends of said section 2. Asfor the finger 7, it may penetrate into the catch 10 unitary with a rod11 fixed to the bottom 12 of the section 1 and substantially parallel tothe axis of said section 1.

FIGS. 2 and 3 show the locking device according to the invention in anembodiment given by way of example.

According to this embodiment, a support 13 is made unitary with thesection 3. It comprises slideways 14 for guiding the fingers 6 and 7. Aconnecting rod 15 is articulated to the support 13 about an axis 16,whilst a ram 17 is connected between support 13 and connecting rod 15.Return tippers 18 are an ticulated about axes 19 on the support 13. Thetippers 18 are provided with grooves 20 which cooperate with lugs 21unitary with the fingers 6 and 7 for controlling the displacement ofsaid fingers 6 and 7. Finally, a threaded rod 22 is connected between ashouldered shaft 23 about which the return tippers l8 and the connectingrod 15 are articulated.

It will be noted that the catches 8, 9 and 10 are constituted byapertures made in the actual walls of the sections 1, 2 and 3. Moreover,switches 24 for controlling the supply and/or delivery of the rams 4 and17 are arranged to be unitary with the section 3. The switches 24 areactuated by cams 25, some of which are unitary with an extension of thethreaded rod 22 and another with an end of the rod 11. These switches 24belong to the assembly for servo-controlling the different movements ofthe rams which makes possible the sequence operation as explainedhereinafter.

The completely closed jib may operate as follows:

The finger 6 is inserted into the catch 8 of section 2 (FIG. 2). Byextending the ram 4, the momentarily integral group of sections 2 and 3emerges from the section 1. It will moreover be noted that, inas much asthe jib is not oriented towards the ground, this movement may beeffected without locking the finger 6 in the catch 8. The finger 6 isthen automatically removed from the catch 8 in order to insert thefinger 7 into the catch 10 of the rod 1 l and thus provisionallyintegrate sections 1 and 3. The section 2 is then returned into thesection 1. Finger 7 is then removed from catch 10 in order to lockfinger 6 into catch 9. Sections 2 and 3 are therefore integrated. It isthen sufiicient to remove the section 2 from section 1, by extending theram 4, in order to terminate the telescoping of the jib.

It will be noted that the two movable sections of the jib have beentelescoped automatically and with a single ram 4, whatever theorientation of said jib. Operation may in particular be carried out withthe jib in any inclined position. This automatic maneuver which iscompletely mechanised, and this possibility of telescoping, which isindependent of the orientation, are new advantages which the machinesknown prior to the present invention did not have. In fact, thepractical use of the new machines according to the invention contributesa simplification of the equipment and a simplicity of maneuver whichwere previously unknown.

It will furthermore be noted that the simplification of the equipment isessentially due to the judicious arrangement of the bolt 5 which enablesit to cooperate with the different catches 8, 9 and 10. The priorarrangements did not enable the different sections 1, 2 and 3 to beselectively integrated with a single bolt, and, consequently, as severalrams 4 and/or several rams 17 were required, were more complex andexpensive than the arrangement according to the invention.

What is claimed is:

1. Locking structure for a telescopic jib constituted by at least afirst outer section, a second section and a third inner section, anelement connected to the first section and by a single motive memberconnected between the first and second sections and comprising at leastone bolt disposed on the rear end of the third section and capable ofintegrating the second and third sections in telescoped positions and inextended positions, the bolt being adapted for selective insertion in atleast three locking catches the first of which is unitary with the rearend of the second section, thus to integrate the second and thirdsections to move them together relatively to the first section, thesecond catch being unitary with the element connected to the firstsection near the front end of the first section to maintain the thirdsection in extended position relatively to the first section afterextension of the assembled second and third sections relatively to thefirst section whereby the second section may be free to move rearwardlyrelatively to the first and third sections, the third catch beingunitary with the front end of the second section to integrate the secondand third sections whereby the assembled second and third sections maybe extended together relatively to the first section, all said rearwardand extended movements being effected by the single motive member.

2. A device as claimed in claim I, wherein the bolt is constituted byfingers mounted to slide in a slideway unitary with the third sectionand capable of being actuated by a ram.

3. A device as claimed in claim 1, wherein the catches are constitutedby apertures made in the elements with which they are unitary.

4. A device as claimed in claim 1, wherein the element with which thesecond catch is unitary is constituted by a rod fixed on the inner faceof the bottom of the first section.

* t 4 IF l

1. Locking structure for a telescopic jib constituted by at least afirst outer section, a second section and a third inner section, anelement connected to the first section and by a single motive memberconnected between the first and second sections and comprising at leastone bolt disposed on the rear end of the third section and capable ofintegrating the second and third sections in telescoped positions and inextended positions, the bolt being adapted for selective insertion in atleast three locking catches the first of which is unitary with the rearend of the second section, thus to integrate the second and thirdsections to move them together relatively to the first section, thesecond catch being unitary with the element connected to the firstsection near the front end of the first section to maintain the thirdsection in extended position relatively to the first section afterextension of the assembled second and third sections relatively to thefirst section whereby the second section may be free to move rearwardlyrelatively to the first and third sections, the third catch beingunitary with the front end of the second section to integrate the secondand third sections whereby the assembled second and third sections maybe extended together relatively to the first section, all said rearwardand extended movements being effected by the single motive member.
 2. Adevice as claimed in claim 1, wherein the bolt is constituted by fingersmounted to slide in a slideway unitary with the third section andcapable of being actuated by a ram.
 3. A device as claimed in claim 1,wherein the catches are constituted by apertures made in the elementswith which they are unitary.
 4. A device as claimed in claim 1, whereinthe element with which the second catch is unitary is constituted by arod fixed on the inner face of the bottom of the first section.